Rust formation occurring inside the bottom portion of metallic reservoirs, such as the very common fuel oil tanks for domestic applications, is well documented in the art. Such rust formation generally involves air moisture inside the reservoir that condenses on the relatively colder inside walls of the reservoir, dribbles down along the sidewalls and, finally, accumulates in the bottom portion of the metallic reservoir or tank. With time, prolonged contact between the accumulated water and the metallic surfaces of the reservoir causes rust formation, particularly around the couplings and joints that are usually found in bottom portion of the latter. Furthermore, other factors contribute to the acceleration of rust formation, such as for example, the presence of traces or chlorides or bacterial contamination in the accumulated water, as well as the presence of sulphur-containing chemicals in the fuel oil which, when mixed with water, forms an acid.
Reservoirs made of metals such as, for example, steel or iron, that include protection against internal rust formation are known in the art. These reservoirs of the prior art generally propose a metallic reservoir having an internal rust-proof coating or internal structure, or a combination of these, which inhibits or at least slows down rust formation on the inside walls of the reservoir.
The prior art internal surface coatings or treatment of the metallic reservoirs generally consist of an epoxy, a ceramic or an electroplated metal.
The prior art internal structures, such as water traps, are generally designed to capture and retain the accumulating water in a specific compartment or recess embedded in the bottom portion of the metallic reservoir. The structure or recess is generally coupled to a drainage outlet through which the accumulated water can be evacuated periodically or on a continuous basis.
While the metallic reservoirs of the prior art, when equipped with an internal rust protection coating or structure, generally fulfill the main objective of storing petroleum products in economical metallic reservoirs, they also have numerous disadvantages.
For example, the metallic surface coating or treatment generally requires a special preparation of the metal surfaces inside the reservoir prior to application of the rust inhibiting treatment or coating. The surface preparation usually consists in sandblasting the metal surfaces, a hard to control operation. Inappropriate preparation can have long-term repercussions on the effectiveness of the surface coating or treatment against rust formation. Furthermore, the preparation of the metal surfaces, as well as the application of the final metal surface treatment or coating, generally requires expensive equipments operated in humidity controlled environments, followed by thorough quality control tests, all of which add up to the complexity of assembly and production cost of the finished reservoir.
Additionally, internal structures comprising a water trap, such as a compartment or a recess integrated in the bottom portion of the reservoir, generally keep the accumulating water in relatively prolonged contact with the inner metallic walls of the latter when the water is not evacuated on a regular basis. Thus, the internal structures only have a limited effectiveness against internal rust formation in the reservoir.
Accordingly, there exists a need for an improved reservoir. It is a general object of the present invention to provide such a reservoir.